- Are taking any of the following: amiodarone, astemizole, bepridil, buspirone, carbamazepine, cimetidine, cisapride, clarithromycin, cyclosporine, dihydroergotamine, diltiazem, ergotamine, erythromycin, flecainide, glucocorticoids, grapefruit juice, St. John's wort, itraconazole, ketoconazole, lovastatin, midazolam, nefazodone, phenobarbital, phenytoin, pimozide, pioglitazone, propafenone, propofol, quinidine, rifabutin, rifampin, rosiglitazone, simvastatin, tacrolimus, terfenadine, ticlopidine, triazolam, or verapamil.